Adverse effects associated with acute air pollution exposures have been well studied;however evidence on effects of chronic exposure has mainly been limited to a few seminal studies of long-term exposure to air pollution. These studies found an increased risk of mortality associated with long-term exposure to particulates. A few recent studies have broadened knowledge in this area, demonstrating an association between adverse health outcomes and chronic particulate exposure, even as particulate levels have decreased somewhat over time in many areas of the US. We are currently conducting one of these studies with data from the Nurses'Health Study (NHS), combining improved exposure, covariate and outcome assessment. In contrast to other studies, a complex GIS modeling process estimates particulate exposure for each address for each participant over a number of years. In addition, we are adjusting for potential risk factors using information that is updated every two years. Results indicate significant associations of chronic particulate matter less than 10 microns in diameter (PM10) exposure with all-cause mortality and fatal myocardial infarctions. Previous studies have indicated differences in the effects of air pollution exposure among men and women;therefore a study of chronic exposure among men would contribute significantly to the literature. We propose to apply the exposure modeling methods which have been developed for the NHS to examine in the HPFS the relationships of chronic particulate exposure with all-cause mortality and cardiovascular disease. PUBLIC HEALTH RELEVANCE: Assessing the relationship of chronic particulate exposures to all cause mortality and cardiovascular disease is of great public health significance. This study will add to the current literature by examining these associations among a cohort of men, as recent cohort studies of chronic exposures have focused on women. In addition, the study will take advantage of exposure models that were developed for a previous study and the use of updated covariate information for the entire period of follow-up.